There is nothing quite like sitting back and staring out at the evening sky looking at millions of stars. Hold on, why are some of those stars moving and why are some in the exact place all the time? Turns out a lot of the things that you and I see in the night sky are not stars. The reality is there are over 3,000 artificial satellites (man mane objects that we purposely flung out into space) orbiting the earth as we speak. With about 1,200 of those being active communication, scientific, government or Elon Musk‘s satellites. And, we have been flinging satellites into space ever since 1957 when the Soviet Union launched Sputnik I and so began the Space Race. For the next 20 years the Space Race captivated the world with photos of the dark side of the moon, Mars flybys, the moon landing and Skylab the first space station.
With all those satellites up there one might ask, how do they stay up there and what happens with them when they run out of juice? The first question of how they stay up there is relatively easily, for an astrophysicist. It’s called orbital velocity, in super simple terms the closer a satellite is to the Earth the faster it must travel to counteract orbital decay (the natural gravitational pull of the Earth). Some satellites orbit the Earth in as little as 90 minutes. Some satellites are in a geostationary orbit, meaning they orbit at a similar speed to the spin of the Earth and appear not to me moving at all. So, what happens when satellites run out of juice or break down? There are basically 3 options: de-orbiting, leaving where it is and hope for the best or pushing it into the graveyard orbit.
Why so many satellites? First, a lot of satellites are private and companies or governments don’t to want to share. Second, satellites need a line of site to communicate. Since we proved the Earth is round in one of our previous podcast, multiple satellites are needed to communicate around the globe. And finally, new technology must make its way to space somehow. You can’t just bring a satellite in for upgrades when it needs a new processor, sensor or camera.
Even though the Space Race is over and nobody has been to the moon since 1969, amazing things are still happening in space and remember the next time you look up at the sky, the sky just might be looking right back at you.